Interstate 585とは 意味・読み方・使い方

Interstate 585 (I-585) stretches from Interstate 85 to Spartanburg, South Carolina. I-585 is co-signed the entire length with U.S. Highway 176 and it uses US 176's exit number system instead of its own. Between exits 23 (I-85 Business) and 25B (U.S. Highway 221) the road is a freeway but has substandard or no shoulders. To the south of exit 25B, U.S. 176 becomes a surface road but there exist I-585 shields in this region (Photos: [1] from [2], [3] from [4]). There also exists a red and blue "I-585 Business spur" shield at U.S. Highway 29 (Photo: [5] from [6]), making it unclear whether I-585 terminates at exit 25B and the road from there to U.S. 29 is I-585 Business, or I-585 extends to U.S. 29.